Chemical abrasion (CA) is a two step method for reducing Pb loss where zircon is annealed then partially dissolved. We use SIMS to find closed and open system zircon domains in zircon that has been CA, annealed only, or untreated. Raman mapping shows to identify lattice damage in SIMS spots. Atom Probe (APT) results from both the discordant spots and concordant ones are all homogenous and identical. Thus APT cannot distinguish discordant and concordant zircon.

The Llanos de Moxos (Bolivian Amazon) host thousands of anthropogenic forest islands from the Holocene. These sites contain shell middens primarily composed of freshwater snails (Pomacea spp.), often used for ¹⁴C dating. To evaluate potential radiocarbon reservoir effects (RRE), modern Pomacea shells and coeval tree leaves were analysed. Results reveal no significant RRE, supporting their reliability for dating archaeological and paleoecological records in the region.

StratoBayes is a novel Bayesian method for aligning stratigraphic data from multiple sites. It integrates diverse information, such as geochemical signals and radiometric dates, and provides robust age estimates with quantified uncertainty for all sites. We use StratoBayes to correlate lower Cambrian δ¹³C records from Morocco with an undated record from Siberia, and estimate the age of the world’s oldest trilobites.

We report 31 new ¹⁰Be and 26 recalculated ³⁶Cl dates from the Sierra Nevada Mountains (USA) and conclude that deglaciation’s final and rapid phase began at 16.4 ± 0.8 ka. In comparing this timing with high-resolution regional paleoclimate proxies, we interpret that rapid deglaciation most likely began at 16.20 ± 0.13 ka, which is indistinguishable in timing from Heinrich Event 1. We interpret that the range’s deglaciation was likely driven by a reunification of the polar jet stream at this time.

Helium gas accumulates over time in minerals, but loss can occur depending on temperature. If partially retained, its loss can potentially be used for determining past surface temperatures. This study uses a model that accounts for complex gas loss to analyze helium retention in two minerals commonly found on the surface of Antarctica. We find one of the minerals retains helium while the other loses nearly all of the gas within hundred years, making it unsuitable as a climate reconstruction.

We present the first community evaluation of the reproducibility of U–Pb zircon geochronology by ID-TIMS. Eleven labs in the experiment analysed aliquots of the same, homogenised, pre-spiked solution of natural zircon. This removed geological bias inherent to using natural zircon grain populations and allowed focussing the study on final lab preparation and mass spectrometry. We discuss remaining sources of inter-lab bias and propose areas of improvement of analytical methods.

Bayesian modelling is often used to refine numerically dated chronological sequences, e.g., by making use of stratigraphic constraints. First, a high-resolution dataset based on luminescence dating is modelled with the dedicated R package BayLum. Then, three Bayesian modelling tools – namely BayLum, Chronomodel and OxCal – are compared using a high-resolution, radiocarbon dataset. Modelling artefacts are identified; the strengths and weaknesses of the models are discussed.

This technical note develops and demonstrates an improvement in how to calculate the temperatures experienced by rocks as they come to the Earth surface due to erosion in mountainous regions. The solution is fast and flexible, and works even in areas where erosion rates have varied through time. The new method has been added to software used to interpret geochronologic data to help discern the history of mountain ranges.

We evaluate different methods for the potassium (K) concentration determination in feldspars and the impact of the K-concentrations on dose rate calculations for feldspar luminescence dating. Our results show discrepancies between published and our measured K-concentrations. Therefore, we emphasise to measure K-concentrations via bulk measurements and single-grain techniques to obtain more accurate results.

Paired low- and high-precision U–Pb geochronology data are evaluated to better understand young bias in laser ablation dates and detrital zircon maximum depositional ages (MDAs). We redefine the reference for MDA accuracy as the true age of the youngest analyzed population and reframe MDA algorithm assessments around validity. This study highlights opportunities to refine MDA research and anticipates continued community efforts to further improve accuracy of laser ablation zircon geochronology.

This study, using ESR, OSL, and LA-ICPMS trace element analyses, reveals significant relationships between quartz OSL/ESR sensitivities and bedrock characteristics. Trace element compositions appear to influence the OSL and ESR-Ti sensitivities, the last being weak in quartz extracted from metamorphic or deformed rocks. Pressure may take a part in OSL/ESR-Ti sensitivities variability while ESR Al intensities could be linked to initial fluid composition and crystallization conditions

U-Pb dating of cave sediments has provided important new time constraints on the evolution of cave-dwelling organisms (including early humans), and of Earth's climate during the past 5 million years. This paper shows that the most common type of U-Pb dating, which uses ²³⁸U and ²⁰⁶Pb, can be inaccurate beyond 2 million years ago. It proposes an alternative type of U-Pb dating, using ²³⁵U and ²⁰⁷Pb, as a more accurate alternative.

Garnet U-Pb dating is useful for dating geologic events. However, contamination by U-rich minerals included in garnet is a risk. Inclusions are often spotted by high-U spikes or large errors in the age. We dated garnets in metamorphic rocks and calculated ages 10–15 Myr older than expected, reflecting contamination by the mineral zircon. We provide recommendations for identifying contamination and suggest that the bulk dating of zircon inclusions in garnet may also provide valuable information.

This paper describes measurements of cosmogenic neon-21 concentrations in a widely distributed mineral standard material that is routinely used for quality control and interlaboratory comparison for measurements of other cosmic-ray-produced nuclides useful for various geochronology applications. Broadly, this facilitates improvement of precision and accuracy of these measurements and their applications in geochronology.

We show that portable X-ray fluorescence can be used to rapidly (c. 90 s) estimate the rate of background radioactivity in sediment used to calculate burial ages in trapped charge dating studies. This procedure involves inputting a measurement of potassium concentration into a set of simple linear equations, defined by a large, training dataset. Results show good agreement with high-precision methods. Our rapid method will help to quickly generate burial age estimates.

We tested the reliability of infrared-radiofluorescence (IR-RF) dating of K-feldspar on samples of known age. We compare several measurement protocols and analysis variants and determine the most appropriate version. Additionally, we compare these results with those obtained using infrared photoluminescence (IRPL), an alternative dating method for K-feldspar, for the same samples. Our results confirm the dating potential of IR-RF and highlight similarities and differences to other methods.

Ice sheet mass loss is adding to sea-level rise, and is expected to increase, but by how much and how fast remains uncertain. Isotopes produced in rock at the Earth’s surface provide records of past ice sheet thinning which help predict future change but are more effective if they are precise enough to determine past changes to the nearest thousand years. The precision of carbon-14, an isotope which is guaranteed to record past change since the last ice age, can be improved.

Conventional (U-Th)/He thermochronology requires accurate calculation of mineral grain volumes, often based on approximations to an ideal geometry. However, there are many instances where knowingly altering the geometry through polishing mineral grains for additional in situ data collection is desirable. This contribution provides a new method to calculate polished grain volume and other derived data for zircon (U-Th)/He thermochronology using no-added-cost modifications of existing workflows.

The uranium-thorium and uranium-lead radiometric dating methods are both capable of dating carbonate samples ranging in age from about 400,000 to 650,000 years.  Here we test agreement between the two methods by 'double dating' speleothems (i.e. secondary cave mineral deposits) that grew within this age range. We demonstrate excellent agreement between the two dating methods and discuss their relative strengths and weaknesses.

Accurate readings on the environmental gamma dose rate are important. Portable gamma-ray detectors, such as NaI or LaBr₃-based, are easy to handle and affordable. Limited information on alternatives, like CZT (Cadmium Zinc Telluride) detectors is available. We tested CZT detectors and found them suitable for in-field deployment. We used simulations and field tests to evaluate the optimal energy threshold for direct dose rate readings, making the CZT system a reliable alternative.

This manuscript presents a new method to date geological events affecting sedimentary rocks. This method relies on the potential for the zircon U-Pb system to be disturbed during fluid-flow, alteration, and metamorphic events in sedimentary rocks. This manuscript presents synthetic datasets for testing the accuracy and precision of the discordance dating method, as well as data from detrital zircons found in the contact metamorphic aureole surround the Alta Stock.

Laser-based dating of rocks and minerals is invaluable in geoscience. This study presents a significant advancement in our ability to model and correct for a process called downhole fractionation (DHF) that can impact the accuracy and uncertainty of dates. We develop an algorithm that quantitatively models DHF patterns. The implications are far-reaching: improved accuracy, reduced uncertainty, and easier comparisons between different samples and laboratories.

We present a set of six standardized time-temperature histories, which we call benchmark paths, that can be used by the low-temperature thermochronology community to evaluate and visualize the sensitivity of thermochronologic systems to the variables inherent in the interpretation of thermochronologic data. As an example, we present a method for “tuning” each benchmark path to eleven published kinetics models (for the apatite (U-Th-Sm)/He, apatite fission-track, and zircon (U-Th)/He systems).

Age-depth models assign ages to sampling locations (e.g., in drill cores), making them crucial to determined timing and pace of past changes. We present two methods to estimate age-depth models from sedimentological and stratigraphic information, resulting in richer and more empirically realistic age-depth models. As a use case, we determine (1) the timing of the Frasnian-Famennian extinction and (2) examine the duration of PETM, an potential deep time analogue for anthropogenic climate change.

We present an approach to U-Pb dating of carbonates using isotopic image maps. The maps are divided into squares called virtual spots. For each virtual spot, statistical values (mean, uncertainty) are used to determine the age. The user can modify the size and location of the virtual spots and select those that give the most robust age. This approach, applied to high spatial resolution images, makes it possible for the first time to obtain satisfactory ages on images as small as 100 µm x 100 µm.

Sediment generation on hillslopes and transport through river networks are complex processes that influence landscape evolution. In this study compiled sand from over 600 river basins and measured its (very subtle) radioactivity to unravel timelines of sediment routing around the world. With this data we empirically confirm that sediment from large lowland basins in tectonically stable regions typically experiences long periods of burial, while sediment moves rapidly through small upland basins.

We have built a database of (U-Th)/He ages and U and Th contents of goethites from various weathering environments. The database contains 2597 (U-Th)/He ages of goethites from 10 countries. The findings presented in this manuscript contribute insights onto the distribution of dated goethites from different environments globally and into the Earth's Cenozoic weathering history.

We obtained a cosmogenic ³He (³He_c) exposure age of 10.9 ka ± 1.1 ka for the youngest lava flow at Volcano Mountain (VM) in Yukon, Canada. Initially, olivine grains from the flow were crushed to release mantle He from fluid inclusions and subsequently fused to release ³He_c from the matrix. However, mantle He was significantly retained in fusions. We circumvented this problem by step-heating powdered olivine at three temperature steps, where the lowest temperature step successfully isolated ³He_c.

We introduce a new statistical method for determining the time of "peak cooling" in thermochronological inversions. Specifically, we focus on the time-temperature paths that intersect the half-maximum cooling isotherm, signifying the zenith or most rapid cooling within a defined interval. The resultant interpolated time distribution provides a systematic metric, particularly applicable for evaluating model cooling characterized by relatively smooth histories featuring a single inflection point.

This note details a development of the (U-Th)/He method for dating apatite crystals in low-temperature thermochronology. Our innovation simplifies analysis protocols for gases (He) and crystals (U, Th, etc.), aiming to expedite data production and enhance study reliability.

Decay of U to Pb in the mineral baddeleyite is used for precisely dating mafic rocks, but some daughter Pb atoms can be ejected out of the crystal, resulting in an age that appears too young. Atom Probe Tomography was used to map the distribution of U and Pb atoms in 3 dimensions within a baddeleyite crystal and estimate the average distance that Pb atoms are displaced by decay of U. This allows us to correct the measured age on a baddeleyite crystal knowing its size and shape.

We investigate the relationship between damage trails from uranium fission in apatite and the etched tracks measured with an optical microscope. We aim to understand sampling biases and to improve etching, selection and measurement protocols. The track orientation and length, apatite and track etch rate, and effective etch time co-determine whether a track is suitable for measurement. Reliable data are attainable because the specific sample properties have but a limited effect on these factors.

As a result of increasing precision and accuracy in geochronology, interpreting complicated age spectra has become increasingly important, since individual mineral ages often do not directly date the actual geologic process of interest. Here we propose a method for estimating the age of eruption or deposition of a set of minerals dated by the U-Pb system which, in contrast to previous approaches, remains accurate even when the dated minerals have experienced loss of the daughter product Pb.

Volcanic ash layers are a common tool to synchronize records of past climate, and their estimated age relies on external dating methods. Here, we show that the chemical composition of the well-known, 12000 year-old Vedde Ash is indistinguishable with several other ash layers in Iceland that are ~1000 years younger. Therefore, chemical composition alone cannot be used to identify the Vedde Ash in sedimentary records.

The Great Unconformity represents an enormous amount of time lost from the sedimentary record. Its origin is debated, in part, due to different approaches used to interpret zircon (U–Th)/He ages. This thermochronometric system is ideal for this problem because the temperature sensitivity varies according to radiation damage. Here we explore the uncertainty associated with the radiation damage model and show how this limits our ability to resolve the origin of the Great Unconformity.

We proposed a new non-destructive mineralogical methodology on inframilimetric grains that allows to quantify the hematite and goethite content and hematite/goethite ratio of grains prior to (U-Th)/He geochronological analysis. (U-Th)/He data performed on different aliquots with different acquisition time shows no remarkable differences in age, opening a new way to investigate the (U-Th)/He data evolution in supergene lateritic duricrusts.

Paleomagnetic data from Cascade Lake (Brooks Range, Alaska) extend the radiometric-based age model of the sedimentary sequence extending back 21 kyr. Correlated ages based on prominent features in paleomagnetic secular variations (PSV) diverge from the radiometric ages in the upper 1.6 m, by up to about 2000 years at around 4 ka. Four late Holocene cryptotephra in this section support the PSV chronology and suggest the influence of hard water or aged organic material.

Prehistoric volcanic eruptions are often dated by wiggle matching series of radiocarbon ages on tree rings to standard calibration curves, ignoring potential contamination by 'old' carbon given off by the volcano. We modeled the effects of low amounts of contamination on wiggle match dates for the 10th century Changbaishan eruption and found evidence of contamination in all. We propose a new protocol to identify the presence of contamination, and provide more secure dates for major eruptions.

The timing and duration of fluid activity within a gold deposit enables a greater understanding of how the deposit evolved and thus help future mineral exploration. This research uses high resolution dating methods to unravel the overprinting fluid activity at the Martabe gold field in Sumatra. Methods outline in this report can be applied to deposits globally.

Potassium-based geochronology, including the ⁴⁰Ar/³⁹Ar and K-Ar methods, provides critical constraints on the timing and duration of many events and processes in earth history. These methods assume that a key parameter, the fraction of potassium with a mass of 40, does not vary in some relevant materials. Some recent work has identified some variability in these materials. This work examines the effects of this variability on calculated K-Ar and ⁴⁰Ar/³⁹Ar ages.